SUMANTA MANNA, BENOY KUMAR SINGH, K JOSEPH MARIA DAS
Turkish Journal of Oncology - 2025;40(2):141-150
OBJECTIVE The complexities associated with RapidArc in treatment planning and delivery have always required pre-treatment quality assurance (PSQA). This study aimed to compare the PSQA results of Fraction- Lab, a phantom-free log file analysis, with 2D array and portal dosimetry (PD) to evaluate appropriate gamma criteria. METHODS Thirty treatment plans each from Head and Neck (H&N) and pelvis sites were analyzed. FractionLab (Varian/ Mobius Medical System) was used for phantom-free gamma analysis of delivered and planned fluences based on log files. PD was performed using an aS1200 EPID, and 3D gamma analysis was conducted using the Octavius 4D 1500 2D detector array. Gamma evaluation in FractionLab was performed using log files from 0.1%/0.1 mm to 1%/1 mm in increments of 0.1%/0.1 mm and compared with global gamma criteria. RESULTS The average gamma passing rates for H&N and pelvis sites using portal dosimetry, the 2D array (3%/2 mm), and FractionLab were 98.68% and 98.17%; 96.79% and 98.79%; 98.31% and 98.02% at 0.5%/0.5 mm, respectively. The portal dosimetry results (3%/2 mm) were statistically comparable with Fraction- Lab (0.4%/0.4 mm–0.7%/0.7 mm). CONCLUSION This study demonstrated the performance and suitability of gamma criteria for FractionLab in a phantom- free PSQA settingand it can serve as a reliable second check for PSQA.
